^  ^  ^  O'V-  ct  6  \ 

i 

The  Sewerage  and  Subsoil  Drainage 

OF  NORFOLK. 


To  THE  Drainage  Committee,  « 

(rentlemm: — I  forward  herewith  a  map  of  Norfolk  showing  the 
lines  of  the  proposed  sewers,  with  indications  of  skes;  also  a  de¬ 
tailed  estimate  of  the  cost  of  the  same. 

The  general  system  was  accurately  foreshadowed  in  my  Prelimi¬ 
nary  Report ;  there  is  no  material  change  in  the  details  therein  sug¬ 
gested.  The  Pumping  Station  is  placed  at  the  north-east  corner  of 
Cove  and  Brew'er  Streets.  The  general  system  is  divided  iido  three 
sections,  as  follows  : 

A.  The  district  drained  by  the  Freemason  Street  maim 

B.  The  district  drained  bv  the  Brewer  Street  main. 

C.  The  district  drained  by  the  Cove  Street  maim 

The  lower  end  of  the  Freemasen  Street  main  is  10  indies  in 
diameter,  and  continues  of  that  size  to  the  intersection  of  Granby 
and  Courtnev  Streets  ;  thence  to  the  end  of  Freemason  Street  it  is 
8  inches  in  diameter. 

The  Brewer  Street  main  is  15  inches  in  diameter  from  tlie  pump¬ 
ing  station  to  Queen  Street;  thence  to  Cumberland  Street  it  is  12 
inches  in  diameter ;  thence  to  Smith  Street  it  is  10  inches  in  diam- 


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oter^  and  thence  to  Denby  Street,  its  upper  end,  it  is  8  inches  in 
diameter. 

The  Cove  Street  main  is  15  inches  in  diameter  to  Fenchurch  St.; 
tlience  to  Holt  Street  it  is  12  inches  in  diameter ;  thence  to  Char¬ 
lotte  Street  it  is  10  inches  in  diameter.  This  main  is  made  some¬ 
what  larger  than  the  demands  of  the  district  now  sewered  by  it 
would  require,  in  order  that  it  may  accommodate  if  necessary  the 
the  future  drainage  of  the  north-eastern  section  of  the  City,  which 
lies  too  low  to  be  connected  with  section  B. 

Section  A  includes  the  district  between  Granby  and  Newdon  Sts. 
as  far  south  as  Main  Street.  Section  B  includes  the  district  be- 
tw^een  Chesapeake  and  Granby  Streets  as  far  south  as  Main  Street, 
and  also  the  district  south  of  Main  Street,  bounded  by  Marsdeii^s 
Lane,  Union  Street,  Newton^s  Lane,  East  Water  St.  and  Hutchins’ 
Lane. 

The  district  south  of  Main  Street  between  Market  Square  and 
Fayette  St.  is  drained  by  gravity  to  the  foot  of  Commerce  St.,  the 
point  of  outlet  for  the  force-main  of  the  pumping  station.  A  small 
district  south  of  Main  St.  and  west  of  Fayette  St.  is  drained  by  an 
independent  system  discharging  at  the  foot  of  Matthews  St. 

The  sub-main  and  lateral  sew’ers  are  mainly  of  6-inch  pipe,  a 
small  proportion  only— about  2000  feet — of  the  laterals  being  of 
8-inch  pipe,  and  the  Fenchurch  St.  submain  being  of  10-inch  pipe. 

As  a  rule,  the  minimum  grade  of  all  sew^ers,  mains,  submains, 
and  laterals,  is  1  to  300  ;  the  exceptions  are  as  follow- s  : 

The  Cove  St.  main  has  a  grade  of  1  to  325  ;  the  Fenchurch  St. 
sub-main  has  a  grade  of  1  to  600  ;  the  Matthews  St.  sewer  has  a 
grade  of  1  to  400  ;  the  west  Water  and  Commerce  St.  sewer  has  a 


) 

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gr^ide  of  1  to  450  ;  tlie  west  Water  and  Union  Sts.  sewer  to  Com* 
)  rnerce  St.  has  a  grade  of  1  to  400  ;  and  the  Cliarlotte  St.  sewer  has 

a  grade  of  i  to  450. 

j,/  Taking  these  grades  as  a  basis^  the  sizes  of  the  pipes  have  been 

regulated  with  a  view  to  their  running  at  no  time  to  more  than  one- 
third  of  their  capacity.  This  is  rather  more  than  the  usual  allow¬ 
ance  but  it  will  add  very  slightly  to  the  cost  of  the  work)  and  will 
provide  for  any  possible  future  increase  of  density  of  population ^ 
also  for  a  considerable  use  of  the  sewers  for  the  discharge  of  manu¬ 
facturing  wastes. 

.  The  force-main  (the  outlet  from  the  pumping  station)  is  12  inches 
in  diameter,  and  its  cost  is  estimated  at  $2500.  There  is  no  doubt 
that  for  a  long  time  to  come,  and  perhaps  permanently,  the  pumps  can 
perfectly  well  force  the  sewage  through  an  8-inch  pipe,  and  I  sub¬ 
mit  to  the  judgment  of  the  Committee,  the  decision  of  this  question  : 
^  whether  the  exigencies  of  economy  ai*e  sufficient  to  make  it  worth 

while  to  take  the  very  slight  risk  that  it  might  be  necessary  at  some 
^  remote  future  day,  to  replace  this  8-inch  pipe  with  a  larger  one,  or 

to  lay  a  second  pipe  to  double  its  capacity.  Of  course  the  risk 
would  be  very  much  lessened  by  laying  a  10-inch  pipe  at  once,  and 
this  would  effect  a  material  saving.  In  making  the  plan  it  has 
been  assumed  that  it  may  be  considered  advisable  to  expend  an  ex¬ 
tra  thousand  dollars  on  this  important  part  of  the  work  ;  but. the 

recommendation  is  modified  bv  the  above  remarks. 

%/ 

The  details  of  the  pumping  station  are  sufficiently  given  in  the 

drawings  and  estimates.  The  drawing  shows  a  brick  chimney  67 

feet  high  and  9  feet  wide  at  the  base ;  but  the  construction  of  this 

chimney  is  not  recommended  at  least  for  the  present,  as  it  is  be- 
5 


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Kered  that  the  smokestack  furnished  with  the  boilers  will  be  amply 
sufficient  for  active  firing. 

The  pumps  selected  are  Blake^s  Duplex  Pumps^  two  sets  each 
with  a  double  pump  and  double  steam  end.  These  pumps  and  the 
boilers  awe  offered  free  on  lx)ard  in  New'  York  for  the  figures  given 
in  the  estimate, 

A  Field^s  Flushtank  is  to  be  built^  as  shown  by  dots  at  the  heads 
of  all  the  laterals.  Their  discharging  capacity  is  generally  the  same 
as  those  in  use  in  Memphis  (112  gallons.)  Three  of  these  tanks  are 
to  be  of  double  capacity,  (diseharging  about  225  gallons),  because 
of  the  low  grade  of  the  sewers  to  be  flushed  by  them.  There  are  in 
all  159  flushtanks  which,  discharging  three  times  in  twm  days,  wdli 
require  for  their  working  about  17,500  gallons  per  day.  * 

The  accompanying  specifications  give  full  instructions  for  the 
performance  of  all  work  connected  with  the  construction  of  these 
sewers  and  their  appurtenances }  but  I  desire  to  call  especial  atten¬ 
tion  to  the  importance  of  ample  engineering  supervision  and  the 
closest  possible  inspection.  For  on  the  efficiency  with  which  this 
part  of  the  work  is  performed,  will  depend  to  a  very  great  degree 
the  efficiency  and  permanent  value  of  the  whole  w^ork.  The  occa¬ 
sion  for  expenditure  has  been  restricted  as  much  as  possible,  with 
due  regard  to  the  requirements  of  the  service.  To  attempt  further 
economy  by  cheapening  or  restricting  the  necessary  supervision, 
would  be  most  unwise. 

The  profiles  accompanying  this  report,  give  the  exact  depth  to 
wdiich  each  sewer  is  to  be  laid  at  each  station  along  the  course,  as¬ 
suming  the  levels  upon  which  the  plan  is  based  to  be  accurate.  It 
will  of  course  be  necessary,  as  the  work  is  constructed,  to  run  new 


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exact  levels  along  the  precise  lines  of  the  sewers,  in  order  to  secure 
perfect  accuracy  of  grade. 

For  the  cleansing  of  the  sewers  when  in  actual  use,  two  systems 
are  adopted,  one  for  the  mains  and  one  for  the  laterals.  The  mains 
are  provided  with  two  manholes,  through  which  cleansing  balls  may 
be  introduced.  These  balls  are  of  about  7-8ths  the  diameter  of  the 
sewer,  are  made  of  metal,  water-tight,  and  are  loaded  with  a  suffi¬ 
cient  amount  of  water  to  reduce  their  buoyancy  to  such  a  degree 
that  they  will  roll  easily  along  the  crown  of  the '  sewer.  These 
balls,  by  restricting  the  water-way,  cause  a  slight  accumulation  of 
head  behind  them,  and  the  current  passes  under  them  with  suffi¬ 
ciently  increased  velocity  to  stir  up  and  send  forward  whatever  de¬ 
posit  may  exist, — the  operation  being  repeated  two  or  three  times  at 
each  cleaning.  This  system  has  been  thoroughly  tested  in  Mem¬ 
phis  and  has  been  found  to  be  most  efficient.  For  the  cleansing 
of  the  laterals  handholes  are  provided,  usually  at  intervals  of  100 
feet.  These  handholes  and  their  construction  are  shown  in  the 
accompanying  sketch ;  their  location  is  exactly  fixed  on  the  map, 
and  on  the  occurrence  of  an  obstruction,  indicated  bv  the  failure  of 

a  house  drain  to  discharge,  the  handhole  is  reached  by  opening  the 
street.  Its  elevated  opening  protects  it  against  the  inflow  of  the 
muddy  water  of  the  excavation,  and  it  affords  ample  room  for  the 
introduction  of  the  arm  for  working  the  cleansing  instrument, 
which  is  usually  nothing  more  than  a  stout  piece  of  telegraph  wire 
long  enough  to  reach  Irom  one  handhole  to  another.  With  care 
in  construction,  and  especial  care  to  leave  no  rubbish  or  other  for¬ 
eign  substance  in  the  sewers,  and  with  a  strict  adherence  to  4  inch 


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house  connections  in  all  cases,  the  liability  to  obstruction  will  be 
very  slight. 

For  the  more  perfect  ventillation  of  the  sewers,  while  introdu¬ 
cing  the  flow  of  house  drains  at  the  bottom  of  the  main,  a  special 
form  of  branch-piece  for  the  connection  of  house  drains  is  used. 
[See  accompanying  illustration.] 

As  indicated  in  my  Preliminary  Report,  while  the  immediate 
removal  of  all  decomposing  organic  matter  is  of  the  greatest  impor¬ 
tance  to  the  sanitary  condition  of  the  City,  it  would  be  difficult  to 
overestimate  the  hygienic  benefit  to  result  from  a  perfect  draining 
of  the  subsoil.  Much  stress  has  been  laid  on  this  leature  of  the 
case  by  those  who  have  preceded  me  in  discussing  the  subject,  and 
they  have  not  overstated  its  importance. 

Fortunately,  the  subsoil  of  Norfolk  is  very  largely  of  a  porous 
character,  and  the  simplest  means  of  underdrainage  will  be  much 

4. 

more  effective  there  than  they  would  be  in  a  more  uniformly ’re¬ 
tentive  subsoil. 

Proper  underdrainage  is  secured  by  the  use  of  agricultural 
drainage  tiles  laid  in  the  trenches  with  the  sewer  pipes  at  the  time 
of  construction,  adjusting  their  sizes  to  the  accumulated  flow  they 
may  receive,  and  delivering  their  flow  into  manholes,  sewers,  or, 
where  possible,  into  flushtanks  lying  at  a  low’er  level  or  at  the 
shore.  By  taking  advantage  of  such  means  of  outlet,  it  will  be 
easy  to  prevent  such  an  accumulation  of  lengths  as  would  require 
the  use  of  large  tiles.  Sizes  ranging  from  1 J  to  2  inches  in  diam¬ 
eter  will  suffice  for  nearly  the  whole  City.  The  cost  of  this  portion 
of  the  work  is  estimated  at  $5,130.00.  This  may  be  somewhat 
modified  in  the  final  arrangement,  which  is  necessarily  controlled 


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by  the  quantity  of  water  met  with  in  excavating  the  trenches  ;  the 
modification,  however,  cannot  be  important  one  way  or  another. 

The  estimate  of  the  cost  of  the  work  herewith  submitted  is  based 
on  a  careful,  detailed  computation  for  different  depths  and  sizes, 
labor  being  estimated  at  $1.50  per  day;  pipes  and  tiles  at  the 
prices  at  which  it  is  believed  that  they  can  be  procured  delivered 
on  the  ground;  bricks  at  $9  and  $13  per  thousand  according  to 
quality  ;  flushtanks  at  $45  each  ;  and  fresh-air  inlets  at  $40  each. 

The  total  cost  of  the  work,  including  10  per  cent,  for  contin¬ 
gencies,  10  per  cent,  for  engineering  and  superintendence,  and  a 
royalty  of  10  cents  per  foot,  is  $141,230.42.  With  proper  busi¬ 
ness  management,  this  estimate  is  much  more  likely  to  be  dimin¬ 
ished  than  to  be  exceeded  in  carrying  out  the  work. 

For  the  protection  of  the  works  and  for  general  sanitary  reasons 
it  is  important  that  the  use  of  the  sewers  be  made  compulsory  on 
thcipart  of  the  whole  population,  and  that  all  plumbing  work  and 
other  drainage  of  private  dwelling  houses,  hotels,  etc.,  be  made 
strictly  in  accordance  with  prescribed  regulations  based  on  the  best 
development  of  the  art. 

In  closing  this  report,  I  beg  to  recommend  as  an  important  aid 
to  the  securing  of  a  good  execution  of  all  details,  that  the  perfor¬ 
mance  of  work  by  contract  be  rigidly  excluded,  all  material  being 

♦ 

purchased  by  the  City,  and  all  work  being  done  by  the  day.  This 
would  be  unimportant  in  the  construction  of  sewerage  works  of 
the  ordinary  kind,  with  the  use  of  large  brick  sewers,  but  where 
everything  is  so  exactly  adjusted  to  the  work  that  it  is  to  perform, 
the  least  deviation  from  the  best  in  everything  may  result  in  serious 
permanent  injury.  I  believe  that  thoroughly  good  workin  small-pipe 


sewerage  can  be  secured  as  cheaply  by  days^  labor  as  by  contract  • 
but  even  if  it  were  to  cost  somewhat  more,  it  is  to  be  remembered 
that  to  provide  Norfolk  with  a  storm- water  system  of  sewerage  on 
the  plan  herewith  submitted,  witluadequate  pumping  works  would 
cost  at  least  $700,000  ;  the  saving,  therefore,  by  this  system  is  so 
great  as  to  justify  any  necessary  increase  of  expenditure  to  secure 
the  very  best  workmanship  and  material. 

It  is  also  worth  while  to  consider  the  fact  that  it  will  cost  no 
more  to  complete  the  whole  system  within  three  months  from  the 
time  of  beginning  the  work,  than  it  would  to  extend  the  construc¬ 
tion  over  several  years. 

I  shall  forward  in  a  fev/  days  a  report  with  estimates  on  the  im¬ 
provements  of  Newton’s  Creek  and  the  Canal  -west  of  Granby  St. 

Respectfully  Yours, 

,  GEO.  T.  WARING. 


Newport,  R.  I.,  June  21st,  1881.  » 


